Jiffybox costs you in the cheapest variant 0.02 Eurocents per hour. That's less than 15 Euro per month for a virtual server with 1 GB RAM, 50 GB hard disc, 2 CPU cores and root access. You can test it for 24 hours for free. And if you sign up this year, they give you a 50 Euro bonus which makes it free for more than three months.
Okay, once you got the server with e.g. a 32 bit Ubuntu, you need to install the libgtk2.0-dev package to get REAL Studio applications running. Use commands like this: "app-get update", "app-get upgrade" and "app-get install libgtk2.0-dev". Now you can upload your app with scp and run it with "nohup pathtoapp &" in the background.
I'm happy that I have now a way to host. This won't use fast cgi as I think the stand alone solution is better for this showcase.
PS: It may be a good idea to make the swap partition 10 GB big just in case your apps need more than 1.5 GB of memory.